Continuous tube forming and galvanizing



Feb. 25, 1964 T. H. KRINGEL ETAL 3,122,114

CONTINUOUS TUBE FORMING AND GALVANIZING 2 Sheets-Sheet 1 Filed May l, 1961 (9m, v ATTORNEYS T. H. KRINGEL ETAL 3,122,114

CONTINUOUS TUBE FORMING AND GALVANIZING Feb. 25, 1964 2 Sheets-Sheet 2 Filed May l1. 1961 INVENTORS THEODORE KRINGEL.

CW TTRNEYS EMIL. WlLK United States Patent 2,114 SONTDIUGUS TUEE ESRMNG ANB GJJVNZEIG neodore 1 ringel, Chicago, and Emil Will-t, Parli Forest, lll., assigner-s to Allied Tube & Conduit Corporation, Blue island, lll., a corporation of illinois Filed Pvlay l, i961., Ser. No. l4l6,699 9 Claims. (Cl. 13-33) This invention relates to a continuous process for torming and galvaniziny tubing of endless strips of steel and it relates more particularly to the processing of endless strips of steel to form tubing in a continuous operation and in the treatment of the external surfaces of the formed tubing for galvanizing as a continuous operation in combination with tubing formation.

lt is an object o this invention to provide a new and improved process for the continuous forming of tubing from endless lengths of strip steel and for continuous galvanizing of the formed tubi g as a continuous operation with the formation of the tubing and it is a related object to produce a new and improved machine for use in the practice ot' same.

Another object is to provide a machine and process for the continuous forming and galvanizing of tubing from sheet steel in a simple and eliicient manner to pro- (luce a galvanized tubing at less cost from the standl or" labor, from the standpoint or material utilization cost, rorn the standpoint of space requirements, from the standpoint of heat and power requirements, and ii' is a related object to produce and to provide a method for producing galvanized tubing havin g improved characteristics and appearance without substan al variation such characteristics and appearance between lengths.

These other objects and advantages of this invention wid hereinafter appear and, for purposes of illustration, but not of limit tion, embodiment of the ii.- vention is shown in ine accompanying drawings in whichlG. l is a schematic ilow diagram of the continuous forming rmd galvanizing of tubing in accordance with the practice ci tnis invention;

FG. 2 is a sectional elevational view of the r'unace for t-e continuous galv ci ing of the formed t ng in nce with the practice of this invention;

llG. 3 is a sectional View taken substantially along e line 3 5 o FlG. 2;

FIG. 4 is a sectional elevational View taken substantial1 f along the line 4-4 of FIG. 3;

5 is a sectional view taken substantially along the line 5 5 or llG. l, and

lClG. 6 is a sectional view taken substantially along o-o or' FiG. l.

the important concepts of this invention reside method and mear' lor the continuous forming and Wing of tubing b; the processing of endless length oi strip scel, the invention will be described with rethe line erence to continuous process for forming the metal tubing d in the processing of the formed tubing in a galvarivng, and shearing operation for cutting the li .red tubing into desirable lengths.

Referring now7 to lil-G. l or the drawings, the tubing forming mill is ted with strip steel 1i? supplied form ot coils mounted on a pay-out reel llifor free rotational movement to pay out strip steel as it is requ' ed by the continuous tube forming mill. Ln a continuous for formi g tubing, the strip steel is processed substantially continuously at a relatively constant rate through the Advancement is effected primarily by engagement between the strip steel and the forming 2 and sizing rolls rotating at relatively constant speed whereby the strip steel is drawn into the mill for processing.

Since the lengths of the steel strip in the coils l2 come to an end after a short period of operation of the mill and since strip is taken up continuously by the mill in its continuous operation, it is essential to provide means for splicing the end of one coil i6 with the leading end 13 of another coil for joinder or" the strips into continuous lengths Without stoppage of the mill in its continuous operation. For this purpose, a loop 2@ is taken in the strip of steel dimensioned to have a length suilicient continuously to feed strip to the mill while the trailing end lo of the strip is stationarily held for splicing, as by welding, onto the leading edge of the new reel which has been displaced into position of use. The loop is formed by feeding the strip l@ under the roller 22 and over the roller 245 to about the roller 26 and haelt over the roller 2S and under the roller E@ into the mill. The rollers are each mounted for free rotational movement while the roller 26 is carried by a carriage 32 having wheels 34 rotatably positioned upon a track 36 t'or endwise displacement of the carriage in one direction to malte Strip available to the mill and in the other direction, responsive to the actuation of the winch 3.? through the cable di), to return the carriage and to reform the loop.

Normally, the carriage is in its retracted position to provide a rull loop of strip steel which rests upon a platform overlying the mill and underlying the track. When the end is reached, a portion adjacent the end is locked in a clamping member lll to hold the end section w. ile the end lo of the coil is joined, as by welding, to the beginning of the next coil in the joiner The operation taires but a few seconds. ln the meantime, the mill continues to draw its requirements of strip from the loop to displace the carriage 32 in the direction away from the winch as the loop is shortened. When the ends of coils have been joined, the clamping device 4d is inactivated to free the strip whereby strip can thereafter be supplied trom the new coil as the winch 38 and cable 4i) are eiective to return the carriage to normal retracted position and replenish the loop in preparation for the next splicing operation. lt will be apparent that the strip lil feeds from the coil through the loop to the mill for continuous operation.

Hereatter description will ce made or" the sequence of operations eiiecte in the mill with the elements in the mill longitudinally aligned for the passage of Strip and the tubing formed diereof continuously linearly therethrough.

Frorn the tubing forming roll section the formed tubing is advanced directly to the seam Welder 50 where the abutting free edges of the strip formed to tubular shape are joined by welding, preferably using a continuous resistance Welder in order to keep the upset on the inside of the formed tubing at a minimum. Gtherwise, it would require the use of a support Within the tubing and/ or an upset removing tool employed in combination with a water suction device. Since sucient space is not available in small diameter tubing for housing such support, upset removal tool and water suctions means, it has been found to be expedient, in accordance with the practice of this invention, to make use of a continuous Welder in the form of a roller adjusted to eiect the major upset on the outside of the tubing where access is available for removal.

When, as in the practice of this invention, the upset is concentrated on the Outside, the upset or dash can be removed by a seam shaving tool 52 which follows immediately after the sem welder. The seam shaver ernbodies a scariing tool which shaves the seam to leave a smooth surface on the outer periphery of the formed tubing and whereby the seam would be concealed except for the presence of a heat line indicated by a dark discoloration of metal oxide lformed along the weld surface.

To this point, welded tubing is continuously formed of strip steel with the exception of the possible short lengths of formed tubing which remain with an open seam in the event of skidding of the tubing `and the machine when the mill is stopped for one reason or another. As a result, in the described continuous processing for forming tubing, an auxiliary Welder 54 in the form of a heliarc Welder may be employed, where desired, to take over the welding operatioin whenever the seam Welder fails to weld the seam of the formed tubing. When employed, an overlap is effected with the stop and start of the mill continuously to weld the seam and to insure closure of the seam Vthroughout the length of the tubing. In actual practice with good controls, it has been found that the heliarc Welder is not essential.

After the tubing has been welded to provide a continuous weld throughout the length thereof, the tubing is advanced from the welders to elements linearly aligned therewith for washing and pickling the outer surfaces of the formed tubing in preparation for continuous galvanizing. The welded tubing 55 is advanced iirst into a housing 53 having a removable cover 6G' for access thereto. The housing is provided with a plurality of axially aligned ring members 62 in the form of headers having a plurality of spray nozzles 64 Iarranged equally spaced about the inner periphery for directing a spray 66 onto the outer periphery of the tubing 56 advanced axially therebetween. Each spray head is connected to a reser- Voir 63 of wash water for recirculating the wash Water from the reservoir through pipe 7i? to the spray head 62. `and from the drain in the housing back through pipe 72 for return to the reservoir. ln the illustrated modiiication'the reservoir is shown alongside the housing but it may equally be arranged in other positions such as beneath the housing. A pump means is interposed between the reservoir and the spray heads for displacement of wash water forcibly to spray the wash water onto the exposed surfaces of the tubing as it passes through the housing. 'Forvpurposes of washing to remove grease and the like, use can be made of an alkali wash which may be represented by a solution of ouncesof alkali per gallon of water and it is preferred to heat the wash water to -a temperature below the boiling point of the alkali solution, such as to a temperature of 200 F. to accelerate removal of grease from the surface.

From the hot alkali wash, the tubing 56 is advanced continuously into the adjacent section of housing 74 in which the tubing is treated with a dilute alkali wash. The housing 74 is similar to that of the housing 53 for the hot alkali wash including spray heads to direct the dilute alkali ,wash onto the periphery of the tubing and with a separate reservoir 76 connected to the headers to Y feed dilute alkali from the reservoir to the headers and connected to the drain in the base of the housing for returning the dilute alkali wash from the housing back to the reservoir. ri`he dilute lalkali Wash isV employed for more complete removal of grease and dirt from the surface of the tubing and the use of the dilute alkali wash following immediately after the strong alkali wash operates to save alkali loss since strong alkali carried on the surface of the tubing from thestrong alkali wash will be recovered in the wash with dilute alkali to supply some ofthe alkali for maintaining the desirable concentration vthereof. rhedilute alkali wash may be formulated to contain aboutZ ounces of alkali per gallon Iand it may alsoV be heated to an elevated temperature such as to a te perature bei w boiling, or up to 200 F. more efectively .to remove grease and other undesirable material from the surface of the welded tubing. Y

VFrom the alkali washes,.the tubing is advanced into afrinse housing 7 aligned endwise with the alkali wash housing and similarly constructed. The rinse housing is fitted with a number of axially aligned spray heads, similar to the rings employed in the alkali wash systems, from which rinse water is sprayed onto the surface of the tubing as it passes Lierethrough to rinse remaining alkali from the surface before passing the tubing into the pickling bath. The rinse water is circulated under pressure from a water supply source to the spray heads and the Water collected in the bottom of the rinse housing can be released tothe drain unless water is at a premium, in which event the water is recirculated with suilicient makeup water to provide for substantial removal of alkali. The rinse water may be used either cold or warm, but it is economically undesirable to invest in Warming the water unless the warm water is recirculated between the housing and a water storage reservoir for re-use.

Twrom the rinse, the tubing 56 is advanced directly into a picking housing et? of similar construction as the wash and rinse housings and separated therefrom only by a separating wall $2. The pickling housing is provided with a pair of longitudinally arranged, laterally spaced apart spray pipes S4 arranged in the upper portion of the housing to overlie the tubing 55 which passes linearly through an intermediate portion of the housing beneath the spray pipes to face the weld seam in the direction of the pipes. The pipes are each provided with a plurality of spray nozzles 86 in the underside positioned to direct the spray 88 angularly downwardly to converge onV the weld seam positioned uppermost in the tubing passingV therethrough. rl'hus the spray is directed forcefully from the spray noz- Zles onto the seam to react with the oxides on the surface which are formed at the weld. Use can be made of conventional pickling solutions for removal of the metal oxide, such for example as an acid solution containing about 30 percent by volume HC1 dissolved in aqueous medium. iFor best results, it is desirable to make use of a pickling solution heated to an elevated temperature such as at a temperature of 10G-120 F., but a heated pickling solution is not essential.

The solution is stored in a suitable reservoir 9u and is connected with the spray heads through lines 92, and 94 and circulation is effected by means of a displacement pump. The reservoir, pump and housing are all provided with a rubber lining to protect the metal parts from the acids of the pickling solution.

From the pickling housing tl, the pickled tubing is advanced into an digned section of housing 9a for rinsing the pickling solution from the surface or" the tubing. The rinse housing following pickling is very similar to the rinse housing vherein water is sprayed from spray rings onto surfaces of the tubing passing therethrough to rinse the pickling solution from the surface.

in the aforementioned alkali washes, rinse, pickling and final rinse, the housings can be of a unitary construction subdivided into separate sections by separating walls each of which is provided with aligned openings dimensioned to enable the tubingrto pass lengthwise therethrough in and out of the housings. Instead, the housings can be separated members with aligned openings in the end walls for the continuous passage of the tubing from one to another without bending.

An important concept of this invention resides in the means and method for continuously galvanizing Vthe formed tubingL as a continuous operation with the described forming, welding and cleaning operations. For

Vthis purpose, it is desirable to contact the cleanedV surface steel tubing with molten zinc :for suflicient timeV to enable theV desired reactions to take place to form the desiredthickness of galvanize on the surface and'itgi's important to carry out the reactions under non-oxidizing conditions, otherwise undesirable oxides ofthe metalwill form at the elevated temperaturesimder which the reactions are carried out.

The desired reducing nunon-oxidizing atmosphere can be nai-ntained by the enclosure ofthe galvanizing zone wi A'in a' sealed housing into which an inert, Y,or reducing maalt@D gas can be introduced for maintenance of a non-oxidizing atmosphere. This can be accomplished by a sealed enclosure but it is preferable to make use of an enclosure which is capable of removal to gain access to the interior of the galvanizing zone but without interfering with the ability to achieve atmospheric control, when in position of use.

The desired characteristics have been achieved in the construction illustrated in FG. 2 of the drawings by the use of a rectangular hood 130 having a horizontally disposed top wall 102, side and end walls 104 which depend perpendicularly downwardly from the edges of the top wall into a trough GS facing upwardly from a frame N3 which extends all about the galvanizing zone. The bottom edges 11G of the side walls are received within the trough for support of the hood on the bottom wall thereof. The trough is at least partially filled with a pulverulent material 112, such as ne sand, into which the lower edge of the side walls become embedded to eect a sealing relationship all around which militates against the flow of free gases all around for atmospheric control. One or more inlets H4 for the inent or reducing gas are pro-vided in the walls of the hood -for introduction of such inert or reducing gases in amounts to maintain a nonoxidizing atmosphere therein.

It has been found that the galavanizing reactions can be carried out more rapidly with greater uniformity when the tubing is preheated t an elevated temperature, such as to a temperature above the melting point temperature for the zinc, such as at 750 F., before being contacted with the molten zinc, although it is not essential to pre heat. When preheating is effected, it is again important to achieve the `desired preheat without exposure of the metal surface to oxidizing conditions, otherwise the metal oxides that would form at an accelerated rate while the tubing is heated to an elevated temperature would interfere with the formation of a suitable galvanize on the surface. ln the illustrated modification, the preheat section comprises a tubular housing l116 which has its center aligned with the line of travel of the formed tubing through the machine `and which communicates with the enclosure litt). inert gas is introduced into the tubular housing through an inlet M8 in the forward end of the tubular member for the circulation of the inert or reducing gas lengthwise through the housing into the hood or enclosure idd to maintain non-oxidizing conditions within the tubular housing during passage of the tubing therethrough.

The tubing can be heated to elevated temperature by the introduction of heat from suitable 'and conventional internal or external heaters but it is preferred to make use of induction heating means 121? within the tubular housing to accelerate the build-up of temperature within the tubing walls in minimum time thereby -to minimize the lengths necessary for the tubular housing.

Having described the preheat of :the tubing and the introduction of the preheated tubing into the inert galvanizing zone maintained to reducing or non-oxidizing conditions, description will now be made of the new and novel means by which the ltubing is maintained in contact with a molten bath of zine as a continuous operation with the tubing forming process.

Referring Inow more particularly to FiGS. 2 and 3, the galvanizing means comprises an elongate, horizontally disposed housing 122 in the form of a trough aligned axially with the line of travel of the tubing for passage of the tubing axially through an intermediate section of the housing from an inlet 124 at one end to the outlet H at the opposite end. The housing is provided with one or more inlets 123 which are connected by a passage 139 to a reservoir 132 of molten zinc with means for displacement of the molten zinc from the reservoir to the inlets at a rate sufficient to maintain the housing substantially filled wtih molten zinc to cover the tubing advanced therethrough. The inlet 32% is preferably, though not necessarily', located in the portion of Ithe housing adjacent the inlet end 124 through which the tubing is introduced into the housing for concurrent flow of the molten zinc through the housing with the tubing and in position to overlie the tubing so as to direct the stream or streams of molten zinc onto the tubing.

The housing is further provided with :a drain opening 18? in the bottom wall lSZ of the housing with a downpipe 184 leading from the drain to the reservoir. The drain opening is of small dimension to enable a thin stream of molten zinc constantly to iiow therethrough but at a rate that is :considerably less than the rate of introduction of molten zinc into the housing less the amount that escapes through the openings so that there will be an overow of molten zinc over the ends of the trough forming the inlet and outlet to the housing but with an amount of molten zinc in the trough to cover the tubing passing therethrough. The drain opening le@ is effective in the event of some failure in operation or stoppage of the machine thereby to drain molten zinc from the housing before -the zinc has cooled to a temperature below its melting point, otherwise the zinc would become sohdied within the housing and thereby render the housing unfit for future use until the solidiiied zinc is passed from the housing or otherwise7 with difficulty, removed.

The zinc in the reservoir can be heated by suitable burners or other heating means to maintain the zinc in the bath at a temperature above its melting point ternperature of about 750 F. and preferably at a temperature above about 850 F. Access means are provided in the hood 16o for addition of pigs of zinc to the reservoir in amounts corresponding to the zinc that is used or otherwise removed with the tubing.

It is important to provide a sufdcient weight of coating of molten zinc onto the surface of the formed tubing but it is undesirable to enable excess molten zinc to be carried off with the tubing thereby to increase the cost of galvanzing and/or prevent bead formation by excess zinc remaining on the outer surface. One means particularly adapted to control the thickness of the zinc coating without bead formation and to provide for removal of excess for return to the reservoir, while in a molten state and while still in a protective atmosphere, comprises an elongate block 15@ of stainless steel or the like formed with a groove 152 extending lengthwise across the top wall E54 in which at least the leading edge portion 155 of the block still extends into the trailing end portion of the hood. The groove 152 in the top surface of the block is adapted to correspond in curvature with a hemispherical section of the tubing to engage the lower half thereof during passage of the tubing lengthwise therethrough. ln the preferred practice, the groove is formed to a diameter correspondint7 to that of the tubing or slightly greater.

Cooperating with the block is a roller lSS mounted for rotational movement about an axis crosswise of the line of travel of the tubing with an annular, arcuate recess lo() formed in the periphery of the roller shaped to correspond somewhat to a hemispherical section of the tubing being processed. As in the block, the arcuate recess loi) is dimensioned to have a diameter corresponding to that of the tubing or slightly greater. The roller is positioned with its lower edge l 2 in endwise alignment with the top side of the recess '1552 to more or less define a circular section therebetween corresponding to the circular section defined by the tubing or slightly greater.

Thus the roller 15S operates to engage the top side of the tubing after it issues from the galvanizing trough to preposition the tubing both in its travel through the galvanizing system and for its subsequent engagement with the grooved block for wiping excess molten zinc from the surface. Some excess zinc will also be removed by the roller upon engagement.

The cooperation between the roller and the block is believed to maite the block eiiective as a wiper for removal of excess molten zinc from the outer wall of the tubing. Such excess zinc is removed while the tubing is still within the hood thereby to provide premature 'freezing of the metal While simultaneously protecting the molten metal from oxidation so that the excesses removed can be allowed to ilow back into the reservoir for re-use.

he block is eective to still leave a desirable amount of zinc as a coating on the outer wall of the tubing. To prevent ilow and bead formation, it is desirable to freeze the metal as soon after wiping as possible. For this Y purpose, use can be made of a water quench, as in the vform of a water spray or flow coat 164 following substantially immediately after the tubing emerges from the hood.

From the galvanizing'section, the galvanized tubingV is advanced sequentially through a series of water spray sections 19t) to cool down the galvanized tubing if the tubing has not otherwise been sufliciently cooled in the freezing step, and, from the cool-down operation, to conventional tube sizing rolls 1%, and from the tube sizing rolls to a traveling shear section 194 where the endless tubing is cut into lengths of predetermined dimension for shipping. The water spray sections are similar to the rinse sections which follow alkali cleaning or acid etch and the tube sizing rolls and dying shear are of conventional construction.

As an alternative, the galvanized tubing, after being cooled, may be processed through a spray housing similar to the alkali cleaning, wherein the galvanized surface is wetted with a chromate and nitric acid solution for reaction to form a surface of zinc chromate whereby still greater resistance to oxidation is secured by comparison with a plain zinc galvanized surface. If a section of the spray housing is devoted to the chromate spray, an additional section should be provided for a Water rinse to remove excess chromate solution from the surface.

As another innovation, the tubing is marked, as by means of a marking roll, after galvanizing as distinguished from the conventional practice of indenting to mark the tubing before galvanizing or even before the formation of the tubing. This is because the marking applied to the surface ofthe tubing before galvanizing becomes iilled with molten zinc so that it would no longer be visible and the marked depressions appeared also to interfere with the proper galvanizing of the tubing surface. Thus the marking roll precedes tube sizing, as indicated by the position 191. Y

lt will be apparent from the foregoing description thatV `vanizing of tubing, means Vfor galvanizing the formed e' tubing asV a continuous operation with continuous forming zof the tubing including a sealed enclosure in linear align- .ment with the tubing forming elements'and Vinterposed .between a tubing cleaning means and a tubing sizing imeans, a heated reservoir of molten zinc, an elongate @trough having end Walls which extend upwardlyV beyond zthe level of the tubing and a bottom wall and which is located within the enclosure in linear alignment with the; Vpath ofV travel of the formed tubing through the machineV vand having an inlet in the end wall nearest the Vcleaning means .and an outlet in the end wall Ytoward the tubing vsiringrneans and through which the tubing passes from the inlet to the outlet through an intermediate portion of the trough, Vmeans for preheating theV tubing prior Vto i entrance into the trough and means for maintaining a nonoxidizing atmosphere within the enclosure means for feedinvdmolten ,zinc from the reservoir into the trough in an amount in excess of that taken up'by the tubing and to cover the tubing during passage through the trough, overllow means at the end portions of the trough for returning excess molten zinc from the trough to the reservoir, and means within the enclosure beyond the trough outlet 'for wiping excess molten zinc from the surface of the tubing.

2. 'In a machine for the continuous forming and galvanizing of tubing, means for galvanizing the formed tubing as a continuous operation with continuous forming of the tubing including an enclosure in linear alignment with the tubing forming elements andv interposed between a tubing cleaning means and a tubing sizing means, a heated reservoir of molten zinc, an elongate trough having 'end walls and a bottom wall and which is located within the enclosure in linear alignment with the path of travel of the formed tubing through the machine and having an inlet in the end wall nearest the cleaning means and an outlet in the end wall toward the tubing sizing means and through which the tubing passes from the inlet to the outlet through an intermediate portion of the trough, means for feeding molten zinc from the reservoir'into the trough in an amount in excess of that taken up by the tubing and to cover the tubing during passage through the trough, overflow means at the end portions of the trough for returning excess molten zinc from the trough to the reservoir, means within the enclosure beyond the trough outlet for wiping excess molten zinc from the surface of the tubing, said trough including a drain in the bottom wall of the trough to drain molten zinc continuously 'from the trough 'out at a rate considerably less than the rate of feed of molten zinc to the trough.

3. A machine as claimed in claim l in which the atmosphere is a reducing atmosphere.

4. A machine as claimed in claim 1 in which the preheat means comprises electrical induction means through which the tubing passes prior to entry into the enclosure.

5. A machine as claimed in claim 1 in which the tubing is preheated to a temperature above about 750 F.

6. A machine as claimed in claim l in which the preeat means comprises a tubular member aligned with Vthe line of travel of the tubing and in direct communication kwith one end of theenclosure.

7. A machine as claimed in claim 6 in which an inert gas is introducedinto the tubular member to maintain an inert atmosphere therein during preheat.

8. A machine as claimed in claim 6 in which a reducing gas is introduced into the tubular member for llow through the tubular memberinto the enclosure for maintaining a non-oxidizing atmosphere within the tubular member during preheat.

9. A machine as claimed in claim l in which the means for removal of the excess molten zinc from" the periphery of thetubing comprises a Vblock having a V'substantially hemispherical groove in' the Vupper surface thereof in lengthwise alignment with the path of travel of the tubing from thetrough and dimensioned to be at least as great as the dimension of the tubingV to engage the underside of the tubing during passage thereof through the groove, and a roller mounted for rotational movement about an axis crosswise of the line of ravel of the tubingand having its lower end portion in lengthwise alignment with the` upper portion of the tubing to engage the upper portion of the tubing during passage for alignment of the tubing witht e grooved block.

References Cited inthe tile of this patent SUNITED STATES PATENTS (ther referenccson following page) f UNITED STATES PATENTS 2,876,132 Worden et a1. Mar. 3, 1959 1,531,730 Bundy M3121, 1925 29274371 Hays, Ma 8f 1960 2,001,683 Paugh May 14 1935 2,975,394 SOImChSI1 11112112 21, 1961 2,024,485 Sussman Dec, 17, 1935 2,932,312 Caplan et al May 2, 1961 2,093,233 Domm Sept 14I 1937 5 3,010,844 Klein etal Nov. 2S, 1961 2,142,485 1411115411 11m, 3, 1939 3,017,494 Mackey Ian. 16, 1962 2,186,788 015011 1an. 9, 1940 d r, 2,748,734 Kennedy June 5, 1956 FORHUN PATENTS 2,771,669 Armstrong et a1 Nov. 27, 1956 701,965 Germany Ian. 28, 1941 2,822,291 Hahn F4114, 195s 10 552,126 Greamain 1441.241943 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIGN Patent Na, 3,122,114 February 25, i964 Theodore H. Kringel et al.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read es corrected below.

Column 2, after line 45, insert the following:

The strip enters a series of aligned conventional tube forming rolls, identified by the numeral 48, whereby the strip is deformed from a flat section to a rounded tubing having the freshly cut edges of the strip in abutting relation to form the seam of the tubing.

Signed and sealed this 14th day of July 1964. (SEAL) Attest:

ESTON G. JOHNSON EDWARD J. BRENNER Attestng Officer `Commissioner of Patents 

1. IN A MACHINE FOR THE CONTINUOUS FORMING AND GALVANZING OF TUBING, MEANS FOR GALVANZING THE FORMED TUBING AS A CONTINUOUS OPERATION WITH CONTINUOUS FORMING OF THE TUBING INCLUDING A SEALED ENCLOSRE IN LINEAR ALIGNMENT WITH THE TUBING FORMING ELEMENTS AND INTERPOSED BETWEEN A TUBING CLEANING MEANS AND A TUBING SIZING MEANS, A HEATED RESERVOIR OF MOLTEN ZINC, AN ELONGATE TROUGH HAVING END WALLS WHICH EXTEND UPWARDLY BEYOND THE LEVEL OF THE TUBING AND A BOTTOM WALL AND WHICH IS LOCATED WITHIN THE ENCLOSURE IN LINEAR ALIGNMENT WITH THE PATH OF TRAVEL OF THE FORMED TUBING THROUGH THE MACHINE AND HAVING AN INLET IN THE END WALL NEAREST THE CLEANING MEANS AND AN OUTLET IN THE END WALL TOWARD THE TUBING SIZING MEANS AND THROUGH WHICH THE TUBING PASSES FROM THE INLET TO THE OUTLET THROUGH AN INTERMEDIATE PORTION OF THE TROUGH, MEANS FOR PREHEATING THE TUBING PRIOR TO ENTRANCE INTO THE TROUGH AND MEANS FOR MAINTAINING A NONOXIDIZING ATMOSPHERE WITHIN THE ENCLOSURE MEANS FOR FEEDING MOLTEN ZINC FROM THE RESERVOIR INTO THE TROUGH IN AN AMOUNT IN EXCESS OF THAT TAKEN UP BY THE TUBING AND TO COVER THE TUBING DURING PASSAGE THROUGH THE TROUGH, OVERFLOW MEANS AT THE END PORTIONS OF THE TROUGH FOR RETURNING EXCESS MOLTEN ZINC FROM THE TROUGH TO THE RESERVOIR, AND MEANS WITHIN THE ENCLOSURE BEYOUND THE TROUGH OUTLET FOR WIPING EXCESS MOLTEN ZINC FROM THE SURFACE OF THE TUBING. 